It’s that time of year. Your bracket is already busted, your eyes are bloodshot from being glued to the television and your couch cushion has begun to form a pretty significant crater beneath you. And there is still oh-so-much great basketball left to be played.

A few giants already have taken their seats — some calmly, some only after throwing the chair against the wall first. Wichita State stumbled against Kentucky in the final second of what might be the best game of this tournament so far. Kansas, sans Joel Embiid, and Duke, in a stunner, and Creighton, looking unlike its hot-shooting self, have all bowed out as well.

Three Big Ten teams — Michigan, Wisconsin and Michigan State — have survived to the final 16.

Now the cards reshuffle, the story lines change and the momentum shifts.

Who was playing well heading into this week hardly matters. It’s all about the matchups ahead.

Among the madness, here are five story lines to watch, starting Thursday:

Michael Conroy, Associated Press

Players on the Michigan State bench reacted in the second half while beating Michigan in the Big Ten championship game Sunday in Indianapolis.

1. The best man standing

I’ve said it before, I’ll say it again: Michigan State is the top dog in the race now that the Spartans finally have gotten healthy, and they’ve done nothing but demonstrate that so far, plowing past Delaware and then gutting one out against a talented Harvard team. The inside-out game of Adreian Payne and Gary Harris will take Michigan State all the way to Dallas, where the Spartans will deservedly cut down the nets.

2. The underdog: Dayton

Who thought the Flyers would be here? Not me. That sector of my bracket is covered in scribbles. Dayton had to get past Ohio State and Syracuse, two mammoths even if they had weaknesses. The Flyers held the Buckeyes and the Orange to a combined 3-for-22 shooting from three-point range. Not all of that was Dayton’s doing — both opponents actually shot horribly on those nights — but it’s clear the Flyers’ defense is nothing to scoff at.

3. The matchup to savor

The weekend slate is chock full of them, but Michigan State-Virginia has me salivating as much as any. Pitting the Cavaliers’ matchup man defense against one of the nation’s most versatile offenses? Yes, please. Something has to give. Virginia won the ACC outright, an achievement that doesn’t come without being tested. Still, Tony Bennett called the Spartans the best team his squad will have played all year. Will the Cavs be able to guard the balanced Spartans — all of whom can step out on the perimeter? Can the Spartans not get flustered by Virginia’s ability to make each possession a battle? All of that lies ahead. Special bonus goes to Louisville-Kentucky, which is going to be absolutely insane for obvious reasons.

4. The wild card

Suddenly, and on the national stage, Kentucky is growing up. The squad built around the nation’s most talked-about recruiting class; the preseason No. 1; the regular-season disappointment that slugged through a lifeless SEC — all of those versions are in the past. Now, there’s a new Wildcats team, one playing as well as it has all year — physical enough to torment teams, athletic enough to cause serious matchup issues and disciplined enough to shut down a smart, talented Wichita State team. At this point, Kentucky does not resemble the No. 8 seed it was handed. Topping Louisville — a favorite for the title game — will be no easy task, but if the Wildcats can handle that, who knows what they’ll do?

5. The upset special

So many low seeds live. Including Dayton and Stanford, there are three teams seeded 10 or lower that play on. But perhaps the most intriguing of them started its journey in the play-in games. Tennessee is a squad that figured it out just in time to make the NCAA tournament, and now the Volunteers are looking pretty darn strong. Their rugged frontcourt, led by forwards Jeronne Maymon and Jarnell Stokes, is a challenge for most opponents, but particularly one that struggles on the interior as much as Michigan does. The Wolverines just overcame Texas’ physical operation, but Tennessee will be an entirely new story. The Vols will get their first big challenge as well in Michigan, and will need to find a way to guard the Wolverines’ bevy of wings. So far, though, Tennessee has resembled a bulldozer, simply crushing everything that stands in the way.